+ | Syscall ABI ready for future implementation

drivers/descriptor/descriptor.h

@@ -55,6 +55,7 @@ extern void irq12();
 extern void irq13();
 extern void irq14();
 extern void irq15();
+extern void syscall();
 
 typedef struct {
 	uint16_t	limit_low;
@@ -113,6 +114,12 @@ typedef struct {
 #define IRQ13 45
 #define IRQ14 46
 #define IRQ15 47
+#define SYSCALL 0x80
+
+#define SLAVE_PORT 0xA0
+#define MASTER_PORT 0x20
+#define EOI 0x20 // End Of Interrupt
+#define FIRST_SLAVE_PORT 40
 
 void	init_gdt();
 void    init_idt();

drivers/descriptor/idt.c

@@ -2,15 +2,13 @@
 
 //INTERUPTION DESCRIPTOR TABLE
 
-static idt_gate_t	    idt[256];
+static idt_gate_t	    idt[256] = {0};
 static idt_register_t   idt_reg;
 
 void    init_idt() {
     idt_reg.limit = sizeof(idt_gate_t) * 256 -1;
     idt_reg.base  = (uint32_t)&idt;
 
-    memset(&idt, 0, sizeof(idt_gate_t) * 256);
-
     set_idt_gate(0, (uint32_t) isr0);
     set_idt_gate(1, (uint32_t) isr1);
     set_idt_gate(2, (uint32_t) isr2);
@@ -48,24 +46,23 @@ void    init_idt() {
 	// We send them Initialization Command Words (ICW)
 
 	// ICW1
-    port_byte_out(0x20, 0x11);
-    port_byte_out(0xA0, 0x11);
-
+    port_byte_out(MASTER_PORT, 0x11);
+    port_byte_out(SLAVE_PORT, 0x11);
     // ICW2
-    port_byte_out(0x21, 0x20);
-    port_byte_out(0xA1, 0x28);
+    port_byte_out(MASTER_PORT + 1, 0x20);
+    port_byte_out(SLAVE_PORT + 1, 0x28);
 
     // ICW3
-    port_byte_out(0x21, 0x04);
-    port_byte_out(0xA1, 0x02);
+    port_byte_out(MASTER_PORT + 1, 0x04);
+    port_byte_out(SLAVE_PORT + 1, 0x02);
 
     // ICW4
-    port_byte_out(0x21, 0x01);
-    port_byte_out(0xA1, 0x01);
+    port_byte_out(MASTER_PORT + 1, 0x01);
+    port_byte_out(MASTER_PORT + 1, 0x01);
 
     // OCW1 (Operational Command Word) It enables all IRCs.
-    port_byte_out(0x21, 0x0);
-    port_byte_out(0xA1, 0x0);
+    port_byte_out(MASTER_PORT + 1, 0x0);
+    port_byte_out(MASTER_PORT + 1, 0x0);
 
         // Install the IRQs
     set_idt_gate(32, (uint32_t)irq0);
@@ -85,6 +82,11 @@ void    init_idt() {
     set_idt_gate(46, (uint32_t)irq14);
     set_idt_gate(47, (uint32_t)irq15);
 
+
+    // Syscall
+
+    set_idt_gate(0x80, (uint32_t)syscall);
+
     asm volatile("lidt (%0)" : : "r" (&idt_reg));
 }
 

drivers/descriptor/interrupt_handlers.s

@@ -388,3 +388,9 @@ irq15:
 	push  $15
 	push  $47
 	jmp irq_common_stub
+
+.global syscall
+syscall:
+	push $0
+	push $0x80
+	jmp irq_common_stub

drivers/descriptor/irq.c

@@ -1,12 +1,12 @@
 #include "descriptor.h"
 
-static isr_t interrupt_handlers[256];
+static isr_t interrupt_handlers[256] = {0};
 
 void    irq_handler(registers_t* r) {
-    if (r->int_no >= 40) {
-        port_byte_out(0xA0, 0x20); // primary EOI
+    if (r->int_no >= FIRST_SLAVE_PORT) {
+        port_byte_out(SLAVE_PORT, EOI);
     }
-    port_byte_out(0x20, 0x20); // secondary end of interrupt (EOI)
+    port_byte_out(MASTER_PORT, EOI);
     if (interrupt_handlers[r->int_no]) {
         isr_t handler = interrupt_handlers[r->int_no];
         handler(r);

drivers/syscall/syscall.c

@@ -20,7 +20,9 @@ void sys_stat(registers_t* r) {
 	printf("Syscall stat : eax == %d\n", r->eax);
 }
 
-isr_t syscall_tab[] = {
+#define NB_OF_SC 5
+
+isr_t syscall_tab[NB_OF_SC] = {
 	sys_read,
 	sys_write,
 	sys_open,
@@ -30,9 +32,9 @@ isr_t syscall_tab[] = {
 };
 
 void syscall_callback(registers_t* r) {
-	syscall_tab[r->eax](r);
+	if (r->eax < NB_OF_SC) syscall_tab[r->eax](r);
 }
 
 void init_syscall() {
-	register_interrupt_handler(SYSCALL_INTERRUPT_NUMBER, &syscall_callback);
+	register_interrupt_handler(SYSCALL, &syscall_callback);
 }

drivers/syscall/syscall.h

@@ -3,7 +3,6 @@
 
 #include "../descriptor/descriptor.h"
 
-# define SYSCALL_INTERRUPT_NUMBER 0x80
 void init_syscall();
 
 #endif

kernel/kernel.c

@@ -40,7 +40,7 @@ void	kernel_main(uint32_t magic, uint32_t addr) {
     init_syscall();
     asm volatile(
 	"mov $1, %eax\n"
-	"int $80"
+	"int $0x80"
     );
     pmm_init(mem_size, bitmap);